As of January 2001 as I write this, WMATA has 192 new rail cars on order, to be delivered later in 2001, to add to its current fleet of 764 rail cars.

The system was originally planned to have a maximum operation of eight-car trains running on 4-minute headways on each line (Red, Blue, Orange, Yellow, Green) during peak hours, and that would provide 2-minute headways where two lines run together on one route segment (Blue-Orange, Blue-Yellow, and Yellow-Green). The current rail fleet is nowhere near large enough to provide that kind of service, and the best density currently available is six-car trains on 6-minute headways on each line, with 3-minute headways where two lines run together on one route segment and on some portions of the Red Line. The station platforms are 600 feet long, long enough for eight-car trains, but apparently WMATA officials and engineers question whether there is enough traction power available in the system's electric power sub-stations to provide for a maximum operation of eight-car trains running on 4-minute headways on each line. The issue of running eight-car trains during peak hours is under study by WMATA as I write this article in January 2001, and the ATC (Automatic Train Control) system as well as the traction power system is being evaluated to see if this is feasible without major upgrades.

Each car is 75 feet long, has standard U.S.-gauge rail wheelbase, and has 75 seats, room for up to 125 standees, and three doors on each side of the car. The cars are powered by electricity supplied by a third rail. They can travel at speeds up to 70 mph. Metrorail cars operate in "married pairs", so the train consist configurations possible are, two cars, four cars, six cars, or eight cars.